The present invention relates to a fluid surface texturing device, apparatus incorporating the same and a kit of parts, the use thereof in texturing a fluid surface and a process for texturing a fluid surface.
Concrete has been used for many years to provide the wearing surface on highways. The popularity of the technique varies from country to country, and even within countries, for example between UK Highway Authorities, for the reasons given below.
Concrete is perhaps the most durable, and easily repaired of all materials for highways etc., but there are three interrelated drawbacks:
1. The surface""s natural smoothness requires texturing for increased friction, and water drainage for the avoidance of skidding and xe2x80x9caquaplaningxe2x80x9d when wet;
2. This xe2x80x9ctexturingxe2x80x9d is usually carried out by a stiff brushing or raking as the concrete sets, which is prone to failure, since all texture surface is lost if there is rain at any time in the first 10 hours or so, of the setting process, or by cutting with diamond-tipped rotary blades which is extremely costly and justified only for retexturing runways for example, and leads to excessive, unpleasant audible noise emission as a driving surface;
3 Texturing produced by these methods rapidly wears under traffic, particularly so in areas where high friction is most needed, at corners and, junctions and the like, hence this is not a long term solution.
Asphalt finishes are less durable and need great care to repair properly, but the random surface pattern of particle size, position and gap widths of the surface layer of aggregate, provides a much quieter driving surface, greater friction naturally, and channels for surface water to occupy if not excessive, and to drain in heavy falls.
As a compromise, many roads are laid with a concrete substructure, and an Asphalt topping.
Much research has gone into trying to get concrete surfaces to imitate the performance of asphalt, resulting in the recent successful trials on UK motorways, of so-called xe2x80x9cwhisperxe2x80x9d concrete. A special, aggregate rich surface layer is laid, but the top few millimeters of concrete are given a set-inhibitor, so that the concrete can be removed, this exposing the tips of the aggregate whilst leaving it partially embedded. This apparently provides a dramatic improvement in the required properties.
Unfortunately this chemical technique requires specialised equipment and trained operatives, and due attention to timing, dispersal of inhibitor, removal of the surface cement binder etc. For this reason the application is limited by cost and convenience.
There is therefore a need for a cost effective and convenient apparatus and method for producing a similar result to that of the chemical technique, and in a wide variety of applications, from footpaths, to motorways; for ornamental addition to concrete surfaces, or for discouraging pedestrians from walking in unsafe locations such as roundabout centres and the like.
Moreover there is a need for an apparatus and method for texturing concrete surfaces with acceptable surface flattener and levelness. A standard test method for determining surface flatness and levelness is given in astmE 1155-87. In particular there is a need for an apparatus and method which is self-regulating in terms of surface flatness and levelness produced for a textured surface, for high quality, efficient and reproduceable operation.
We have now surprisingly found a cost effective and convenient apparatus and method for texturing a concrete surface by mechanical means to produce a similar result to that of the chemical technique.
In its broadest aspect there is provided according to the present invention a device for association with a rotatable powered roller having an elongate cylindrical roll surface adapted to be moved over a surface of newly laid fluid and surrounding formwork, wherein the manner of association is such that the roller surface comprises an elongate substantially cylindrical texturing portion and at least two guide portions, the guide portions being adapted to support the texturing portion at a required level with respect to the fluid surface in manner to ensure partial embedding of texturing material distributed thereon.
Reference herein to formwork is to any vertical surround as necessary in the art to provide a boundary for casting a setable fluid, and includes an edge, cutaway or section of existing surface which is to be infilled or repaired.
Reference herein to a fluid is to any setting, curing or solidifiable fluid commonly used in the construction of load bearing surfaces such as footpaths, roads and the like. In particular, the fluids may include concrete and mixtures thereof with other construction materials.
Reference herein to texturing is to incorporation of a solid aggregate for the purpose of inducing a friction, drainage, decorative or ornamental, obstructive, guiding or marking surface and the like.
The aggregate material as hereinbefore defined may be any solid particulate or shaped object. The material may be comprised of any desired wearing, friction inducing, decorative, obstructive or non-obstructive material such as stone or gravel chippings which may be natural or coloured, depending on the effect required, glass fragments, ground glass, concrete or other composite blocks or formed objects and the like. The aggregate material may be of substantially uniform size or may be of a size distribution selected for graded or random texturing.
A device as hereinbefore defined may be integral or non-integral with a powered roller as hereinbefore defined. A non-integral device may be adapted to engage with or to be attached to the roller. The device may be of fixed or variable nature, or may be one of a plurality of super-imposable devices, whereby the required level of the texturing portion may be selected as desired. It will be appreciated that the required level may vary widely according to the desired purpose and function of texturing, but is generally determined to be in the range of 50 to 80% of the average dimension of the aggregate material to be employed. A desired level may therefore be in the range of 2 mm-200 mm.
For example the required level for providing friction or drainage to a surface may be in the range of 2 mm-10 mm, preferably 3 mm-8 mm, whereas the required level for the purpose of introducing a barrier or obstruction to discourage access by humans or vehicles maybe of the order of 10-200 mm, and the required level for introducing guiding or marking texturing, for example to provide a footpath direction strip for the blind or a visible direction marker to indicate or segregate the paths may be in the region of 5 mm-20 mm, for example 7 mm-15 mm.
In a first aspect of the invention a device comprises two substantially identical sleeves which may be fitted around the rolling surface at either end thereof, the sleeves being constructed of any rigid load bearing material and having a sleeve-wall thickness corresponding to the required level as hereinbefore defined. Preferably each sleeve includes a base of one end having an aperture to receive the supporting axis of the roller, and adapted to abut against the end of the roller thereby maintaining the sleeve in place. The sleeve may include additional projections, attachments and the like for the same purpose, and preferably being readily engaged or released by hand or by simple tool.
A plurality of sleeves may be provided of different internal and external diameters, whereby a required level of the texturing portion of the roller may be obtained by means of placing one or a plurality of sleeves one about the other at each end of the roller. Alternatively a set of sleeves may be of similar internal diameter and of different external diameters, whereby a pair of sleeves may be selected to provide the required level.
In a second embodiment a device comprises a pair of support carriageways adapted to ride on, or near the formwork, and having a vertical aperture or the like to receive the ends of the roller. A carriageway riding on the formwork may comprise a friction surface adapted to enable it to slide, whereas a carriageway riding near the formwork may comprise a wheel base or the like. Each support carriageway may comprise sections enabling the height thereof to be adapted, whereby the required level of the texturing portion of the roller may be obtained, or may comprise a stepped surface having apertures or attachments at different elevations. Alternatively a pair of support carriageways may be selected from pairs of different heights. Alternatively each carriageway may comprise an asymmetric continuous or polygonal sleeve or annulus adapted to be located about each end of the roller, and to be rotated such that the guide portion riding on or near the formwork is of the required distance from the roller axis, thereby providing the required level of the texturing portion.
A rotatable, powered roller as hereinbefore defined may be any roller known in the art, preferably for striking the surface of newly laid concrete by being moved over the surface with the roller surface in slipping contact with the fluid surface and with opposite ends of the roller maintained at the required level of the fluid surface, in order to produce a smooth finish to the surface of the fluid. The roller may be of any desired weight to give the desired compression, and the weight may be adapted from one surface to another or indeed from the first striking stage to the second texturing stage by known means. Preferred means includes introducing a medium such as fluid (water) via entry points in the ends or surface of the roller.
The roller may be part of, or incorporated in, a xe2x80x9cpaving trainxe2x80x9d comprising from its leading end, to its following end a moveable hopper to spread the fluid, diagonal or other spreaders to distribute the fluid and control any surcharge of fluid, pokers or other vibrators to remove air, the striking off roller, a second hopper to spread the aggregate material, and a second roller having a texturing portion as hereinbefore defined. This is of particular advantage in laying and texturing rapidly setting surfaces or in the interests of economy in remote areas or for extensive surface areas. A preferred roller includes the roller described in co-pending unpublished International patent application PCT/GB96/01997, the contents of which are incorporated herein by reference. The preferred roller is adapted to be removed from the remainder of the apparatus and dismantled, when not in use, into constituent, smaller parts, and to be re-assembled with use of only some of the constituent parts or with use of all of the parts together with additional parts, whereby the length of the roller may be adapted in convenient manner. The roller suitably comprises internal stressing means for applying longitudinal compression to the roller, between the ends of the roller, so as to reduce the tendency of the roller to sag or become permanently bowed. It is a particular advantage that the roller may be provided as a kit of parts whereby it may be used with enhanced accuracy and convenience on any dimension fluid surface.
A device according to the present invention for use with any such dismantleable roller may be in the form of a roller part of increased diameter which may be readily inserted at the ends of the roller, or may be in the form of a sleeve to be located around a roller part, in place of or together with additional roller parts as desired.
A device comprising a sleeve as hereinbefore defined for use with a conventional non-dismantleable roller may be hinged or resiliently deformable, in manner that it may be expanded about a line parallel to the axis thereof, to provide a lengthwise aperture sufficient to receive the roller, and may be contacted in manner that smooth rolling action is achieved.
A device according to the present invention may conveniently be constructed of any desired natural or synthetic material having the necessary load bearing and substantially resiliently or non-deformable properties, preferably from suitable polymer, metal or composite materials such as steel, aluminium, bronze, nylon, polythene and the like.
It will be appreciated that a device as hereinbefore defined may be readily and simply assembled, attached or associated with a roller in the course of preparing a fluid surface. Moreover the operation of the roller in association with the device requires the same skill and technique as required for operation of the roller itself.
In a further aspect of the invention there is provided a kit of parts comprising one or more devices as hereinbefore defined. Preferably a kit of parts comprises in addition a rotatable, powered roller which is adapted to be removed from the remainder of the apparatus and dismantled, when not used, into constituent, smaller parts as hereinbefore defined. It is a particular advantage that a variety or selection of devices adapted for different purposes may conveniently and compactly be provided in the form of a kit.
In a further aspect of the invention there is provided the use of a device or a kit as hereinbefore defined for texturing a fluid surface. Texturing may be for any desired purpose, such as to provide a friction, drainage, decorative or ornamental, barrier or obstruction, guide or marking surface and the like. Preferably a fluid surface is a surface of newly laid concrete for a highway, footpath or drive, or for a, optionally selective, road or footpath obstacle or obstruction such as a bollard or the like preventing vehicle, motorbike, cycle or pedestrian access, optionally for a vehicle or the like above a given weight or ground clearance. Alternatively texturing may be for the purpose of guiding or marking, for example aggregate material in the form of spheres may be laid in a strip along the length of a newly laid concrete footpath, to provide the familiar foot-sensitive guide for the blind, or in other form for the purpose of segregating or distinguishing distinct pathways and the like.
In a further aspect of the invention there is provided a method for texturing a fluid surface comprising:
distributing aggregate material over the fluid surface in random or predetermined manner;
at a predetermined time thereafter moving a rotatable, powered roller over the fluid surface having the aggregate material thereon, with a texturing portion of the roller surface at the required level above the fluid surface, in order to produce a textured finished surface of the fluid; and
allowing the fluid to set, cure or otherwise solidify.
Preferably the method comprises:
providing a quantity of fluid within formwork; and moving a rotatable, powered roller over a surface of the newly laid fluid, with the roller surface in slipping contact with the fluid surface and with opposite ends of the roller maintained at the required level of the fluid surface by means of the formwork, in order to produce a smooth finish to the surface of the fluid; and
at a predetermined time thereafter texturing the surface as hereinbefore defined.
The aggregate material may be applied by hand or may be distributed from a hopper or a reservoir located in association with the roller or mounted on the formwork whereby it may be distributed directly after preparing the smooth fluid surface, or directly prior to the texturing thereof.
The various stages of the process may be carried out at predetermined times whereby the fluid is prevented from setting prior to texturing thereof, or is allowed to set to a predetermined consistency prior to the texturing thereof. Preferably the concrete is laid and smooth finish applied, whereafter the concrete is allowed to set for up to three hours and aggregate material is applied and the surface textured as hereinbefore defined, whereafter the concrete solidifies in a further six hours or so. This would provide a suitable textured surface for a highway, having adequate embedding and retention of aggregate material.
The texturing may be achieved in one or more passes of the roller over the formwork, or with one or more devices, to gradually achieve the end result of texturing the surface and pressing the aggregate into the surface.
In a further aspect of the invention there is provided a textured fluid surface obtained by the method or with use of the device of the invention.